High texture appearance,the body adopts arc shape, the surface is treated by baking paint, and the plane non reaction hande is adopted,which is easy to operate,safe and reliable.The rectangular multi-layer glass viewing window can be used for the observation of the test objectin the test. The window is equipped with an anti per spiration electnic heater device to prevent the condensation of water droplets, and the high brnighitness PL fluorescent lamp keeps the lighting in the box.